Fifteen months after promising a federal judge he would surrender his medical license, heart surgeon Alex Zakharia still has a clear license in the state of Florida. The 70-year-old surgeon has admitted in court documents to memory problems that were getting worse. Other court documents have linked his work to ''numerous patient deaths'' at the former Cedars Medical Center, which is now the University of Miami Hospital. In April, Zakharia changed his mind about surrendering his license, and the state filed an administrative complaint to investigate his behavior. That complaint is still working its way through the system.